iconphoto() method is used to set the titlebar icon of any tkinter/toplevel window. But to set any image as the icon of titlebar, image should be the object of PhotoImage class.
Syntax:
iconphoto(self, default = False, *args)
Steps to set icon image –
from tkinter import Tk
master = Tk()
photo = PhotoImage(file = "Any image file")
master.iconphoto(False, photo)
Set the titlebar icon for this window based on the named photo images passed through args. If default is True, this is applied to all future created toplevels as well. The data in the images is taken as a snapshot at the time of invocation. If the images are later changed, this is not reflected in the titlebar icons. The function also scales provided icons to an appropriate size.
Code #1: When PhotoImage is provided.
Python3
from tkinter import *
from tkinter.ttk import *
master = Tk()
p1 = PhotoImage( file = 'info.png' )
master.iconphoto( False , p1)
b = Button(master, text = 'Click me !' )
b.pack(side = TOP)
mainloop()
|
Output:

Exception: If you provide an image directly instead of PhotoImage object then it will show the following error.
Code #2: When PhotoImage object is not provided.
Python3
from tkinter import *
from tkinter.ttk import *
master = Tk()
master.iconphoto( False , 'info.png' )
b = Button(master, text = 'Click me !' )
b.pack(side = TOP)
mainloop()
|
Output:
Traceback (most recent call last):
File "C:\Users\Admin\Documents\GUI_python\geeks.py", line 14, in
master.iconphoto(False, 'info.png')
File "C:\Users\Admin\AppData\Local\Programs\Python\Python37-32\lib\tkinter\__init__.py", line 1910, in wm_iconphoto
self.tk.call('wm', 'iconphoto', self._w, *args)
_tkinter.TclError: can't use "info.png" as iconphoto: not a photo image